Method of and means for facilitating the sterilising of apparatus for steam treatment of liquids



H. L. MURRAY 2,815,289 METHOD OF AND MEANS FOR FACILITATING THE STERILISING Dec. '3, 1957 OF APPARATUS FOR STEAM TREATMENT OF LIQUIDS Filed May 18, 1953 A 3 Sheets-Shet 1 Dec. 3, 1957- H. L. MURRAY 2,815,289

' METHOD OF AND MEANS FOR FACILITATING THE STERILISING 0F APPARATUS FOR STEAM TREATMENT OF LIQUIDS Filed May 18, 1953 s Sheets-Sheet z H. L. MURRAY 2,815,289 ANS FOR FACILITATING THE STERILI TEAM TREATMENT OF LIQUIDS SING METHOD OF AND ME OF APPARATUS FOR 5 Filed May 18, 1953 5 Sheets-Sheet 3 fi/vzy Lan /v Mummy V By" 4/ United States Patent METHOD OF AND MEANS FOR FACILITATING THE STERILISING 0F APPARATUS FOR STEAM TREATMENT OF LIQUIDS Henry Lamont Murray, Auckland, New Zealand, assignor to Murray Deodorisers Limited, Auckland, New Zealand, a corporation of New Zealand Application May 18, 1953, Serial No. 355,512

Claims priority, application New Zealand May 28, 1952 9 Claims. (Cl. 99216) This invention relates to a method of and means for facilitating the sterilising of, and/ or flow control through, and/or voiding of liquid form, apparatus for the heat treatment of liquids, wherein there are provided at least two interconnected chambers, the pressure in one chamher being less than that in the preceding chamber and wherein automatic valve means are provided between such chambers which while permitting the passage of liquid therebetween ensures that a liquid seal to prevent or substantially prevent the passage of vapour or gas is maintained during normal operation of the apparatus. The invention is particularly though not solely applicable to apparatus for the heat treatment of liquids wherein said interconnected chambers are operatively connected with a condenser or condensers. Such a type of apparatus is the steam distilling apparatus sold under the registered trademark Vacreator.

In previous known apparatus of the type generally described above, it has always been a recognised disadvantage that the construction and arrangements did not sufiiciently permit of ready sterilisation and cleansing of the assembly or installation, and this shortcoming or disadvantage was particularly apparent where the liquid treated was destined for ultimate human consumption. It is obvious that it is a matter of very considerable importance if possible that during treatment such liquid should not be exposed to the risk of bacterial or other contamination, due to inefficient or insufficient sterilisation of the apparatus or assembly prior to use. Bacterial contamination arises from two main sources, namely, the liquid that remains within the installation generally after a run and also from the liquid seal between the chambers which would, if not removed, be a fertile source of bacterial activity.

Particularly in the case of installations which were in daily use, it was found impracticable, owing to the time factor involved, to provide any really adequate sterilisat-ion before or after the daily run, with the result that sterilisation very frequently took place at such long intervals that adequate sanitation was not provided.

One of the material difficulties lay in the fact that the valve mechanism between successive chambers did not permit of the steam or other sterilising medium being passed through at the end of the run.

For the first time by the present invention there is provided .an apparatus or installation of the type described in which adequate sterilisation of the whole installation may be effected daily or as required before each runa result which heretofore has been entirely impracticable with an installation in constant daily use. To give one example, milk and cream for human consumption can now be processed under such hygienic conditions that the requirements of the most rigorous health authorities should be met with ease.

In previous apparatus of the type described, the valve means between the interconnected chambers do not permit the free and relatively unobstructed passage of a suitable sterilising medium such as steam of suitable ice temperature prior to the normal use of the apparatus. Further said valves at present in use do not permit the liquid forming the seal to be expelled through the valve for subsequent collection or disposal at the close of normal operations.

By the present invention, there is provided valve mechanism which, normally will permit the substantially un= interrupted flow of the liquid being treated, but can be so operated or adjusted that said valve means will not only permit when required free and substantially unobstructed passage of the sterilising medium, such as steam, throughout the installation or apparatus, but will also ensure substantially complete expulsion and subsequent removal of the liquid forming the said seal at the close of normal operations.

According to the present invention, the valve mechanism is so disposed in the installation, and the liquid seal which is formed under normal operative conditions is itself so located that, on the valve being operated to a predetermined degree beyond its normal operative point, the difference in pressure between the two chambers may be utilised to expell or assist in expelling the liquid seal.

Further, according to the present invention, there is provided a valve controlled connection between adjacent chambers in apparatus for the treatment of liquids, which chambers are intended for operation at different pressures, wherein automatic regulation and maintenance of the liquid seal is achieved throughout normal operation, so that there is a continuous flow of liquid therethrough substantially unimpeded by the valve mechanism, said value controlled connection being comparatively simple, self-contained, small and compact, and characterised by its rugged construction, relative freedom from breakdown in use or necessity for close supervision by the operator, its low first cost, its long life and certainty and reliability of operation.

By the present invention, the whole installation, including the condenser or condensers, may be subjected to the cleansing effect of a flow of steam of suitable temperature as desired either prior to the days run on liquid, or at the close of the run after the remaining liquid forming the said liquid seal has been expelled. When the said apparatus or installation has incorporated therewith a condenser having the attributes described in the specification of United States application for Letters Patent Serial No. 110,516, which issued as Patent No. 2,701,681, it will be abundantly clear that for the first time an installation or apparatus of the type described which is readily cleansed and sterilised has been produced,

In one aspect the invention may therefore be said to comprise a method of sterilising an installation or apparatus of the type described including the step of intro du'cing a sterilising medium such as steam of suitable temperature and passing same through the interconnected chambers and condenser and/or other component parts, the valve or valves between said chambers being opened beyond normal operation point to permit the passage of the sterilising medium freely therethrough.

In another aspect the inventon comprises a method of sterilising an installation or apparatus of the type described, including the step of introducing a sterilising medium such as steam of suitable temperature into the installation and passing same through the interconnected chambers, the valve or valves between said chambers being opened beyond normal operation point to permit the passage of the sterilising medium freely therethrough and/or to permit the substantially complete expulsion of the liquid forming the seal.

In still another aspect the invention comprises a method of sterilising an installation or apparatus of the type described, wherein the apparatus or installation can be adequately cleansed by the introduction of the sterilising medium at one point in the apparatus.

Again the invention comprises apparatus of the type described, wherein the automatic valve between the interconnected chambers is capable of being further opened by the operator when desired and is so disposed arranged and operating in relation to said liquid seal that on being further opened by the operator to the desired extent, the difference in pressure between said chambers may be utilised to expel or assist in expelling the liquid seal.

Theinvention consists in these features and in the further features and/or combinations of parts hereinafter pointed out.

A preferred form of the invention, and a modification thereof, will now be described with reference to the drawings filed herewith.

In the drawings, Figure 1 is a diagrammatic elevation showing the preferred form of the invention applied to steam distilling apparatus as sold under the registered trademark Vacreator.

Figure 2 is a vertical section through the gullet outlet from the higher pressure chamber of such apparatus to the lower pressure chamber, and through the associated valve-controlled passage, showing the valve and float and controlling or adjusting means therefor, the valve being shown closed.

Figure 3 is a pictorial drawing showing the construction and mounting of the butterfly valve.

Figure 4 is a plan of the butterfly valve and associated parts, on a larger scale, showing how the knife edge pivots are retained in their grooves, the gullet outlet and associated passage, and the flanges associated with each, being shown in broken lines as they would appear in section on the line 55, Figure 2, and

Figure 5 is a vertical section through the gullet outlet from the higher pressure chamber of similar apparatus to the lower pressure chamber, and through the associated valve-controlled passage, showing the valve and float and a modified form of controlling or adjusting means therefor.

Referring particularly to Figure 1 of the drawings, 1 is a pasteuriser, 2 is a relatively high pressure chamber, and 3 is a chamber of lower pressure, the liquid inlet into the pasteuriser being shown at 4 while the liquid outlet from the chamber 3 is shown at 5. The condenser which is preferably of the type disclosed in the said specification of the United States application for Letters Patent Serial No. 110,516, now Patent No. 2,701,681, is shown at 6. 7 indicates the equilibrium control valve, while a steam inlet into the pasteuriser is shown at 8.

For more thorough understanding of the purpose and scope of my present disclosure, momentary consideration may now be given advantageously, by contrast, to conventional and known vacuum flash pasteurization equipment such as is typically shown in my prior United States Letters Patent to R. L. Murray, No. 2,314,455.

In assembly disclosed therein, I provide a float valve of conventional type between the second and third vacuum stages. And in that assembly, just as with the apparatus of the present application, it is highly desirable that the assembly be sterilized at periodic intervals. Illustratively and if at all feasible, this should be just prior to a new days run.

In order to emphasize, however, that this is virtually impossible with known equipment, we will assume for discussion that in a typical instance and employing known equipment, the apparatus has already been emptied of residual liquors. This, as a result of the run for the preceding day, followed by attempted dismantling and washup. With discharge to the atmosphere of residual product which, at the end of a run, remains at the bottom of the second stage near the valve, the liquid thus discharged represents net loss. This loss ranges as high as from four to five gallons of product. Typically, if removed at all,

4 it is rinsed out with water. Thus, with the prior Murray apparatus and following emptying, the equipment is finally readied for sterilisation.

To this end and referring to the patented Murray disclosure and following typical known procedure, steam is admitted through inlet 21 into the pasturizer 1. The steam then passes through connecting pipe 22 and equilibrium valve 24 to deodorizer 2. This chamber 2 has substantial diameter and length. It will be recalled that during clean-out, attempt at sterilization by steam is under atmospheric conditions, and is not under vacuum. Because of these substantial dimensions, no difliculty is encountered by the steam in flowing through chamber 2 down to the connecting pipe 43 at the bottom thereof. Adequate sterilization to this point is quickly achieved. That this is so can quickly be determined simply by touching the bottom of chamber 2, near valve 42. It will be found that this chamber is almost unbearable to the touch.

Moreover and in this typical prior assembly, some of the steam will pass upwardly through chamber 2 to and through vapor pipe 12 to condenser 4. Sterilizing action will take place in the condenser. The steam is discharged through the outlet thereof to the atmosphere.

But difficulty is encountered with this prior Murray disclosure, typical of known vacuum flash pasteurizing equipment, in sterilizing the high-vacuum line. This line is comprised largely of the low-pressure chamber 3 and pipe 43. Inspection of Figure 2 in my prior patent shows pipe 43 to be connected to the bottom end of chamber 2 through float valve 42 which controls flow from chamber 2 to pipe 43. Moreover, this earlier patent discloses recognition of necessity for thorough sterilization. There I attempted to accomplish this by providing steam cleansing pipes 23 and 23A.

But with my prior disclosure, and with steam admitted into the top of chamber 3, perhaps through pipe 23A and certainly from a second source of sterilizing steam, separate from inlet 21, dual difliculty is immediately encountered. First, two or more steam inlet sources are required, rather than a single inlet.

The second and more important difiiculty is as follows: It is true that chamber 3, similar to chamber 2, possesses substantial diameter and length. When steam is introduced into the top of chamber 3 no particular difficulty in flow thereof is encountered in this region. And part of the steam admitted through inlet 23A goes right down through chamber 3 directly to the discharge pump (not shown) through outlet 50. This pump, of course, does not operate during steam sterilizing.

But part of the steam will go to the left in the drawings of the Murray patent. Now, if this arrangement were to operate properly, thereby ensuring rapid and thorough sterilization, the steam should progress rapidly down the connecting pipe 43, and sterilize the region thereof. But it is right here where difliculty is encountered with the known constructions. For this passage 43 is of comparatively small diameter. By direct consequence, as the steam undertakes to move forwardly and downwardly, there is no way for the air entrapped in that region to pass in counter-flow thereto. The better to understand this, it should be remembered that when it is at rest, the valve 42 in Figure 4 is seated in its closed position. And hence it blocks the passage of air and steam. Since the air entrapped in passage 43 is heavier than steam it remains in the passage and prevents the steam from passing down this latter. This air cushion serves as an effective block in the region of passage 43 and prevents the steam from sterilizing this part of the system. That this is so can be readily determined by the same test heretofore indicated, namely by placing the hand on the connecting pipe 43, on the down-stream side of the valve 42. It will be found that this passageway is cold to the touch. This means simply that the steam is not reaching that portion of the system. Since steam is not reaching here,

'5 this region is not undergoing sterilization. And since it is not sterilized, it becomes a source-of contamination.

In practice and in the use of such known systems, it is found that considerable time must pass before the air can gradually escape through pipe 43 in counterflow to the cleansing steam so that the steam can thereupon have access to the bottom of the passageway 43 and through it to the valve 42. However, until this condition is established, complete sterilization cannot be achieved. And this, in that region where sterilization is most important, i. c. at the valve 42 itself. Furthermore, even with effective sterilization achieved on both sides of the valve, there is still no complete assurance that sterilization will occur right where the valve is located, in the region of its valve seat.

While a possible solution might be to bleed the bottommost part of the connecting pipe 43 at the region of the valve 42, it is apparent that were this expedient to be employed, this would mean that three separate operations would be required to produce sterilization. And even then, as is evident upon reflection, no complete assurance exists that the valve seat itself will be sterilized.

It is to avoid these many difliculties, serious in nature, that I have evolved my new method and as well, my new apparatus for carrying that method into execution, in my new method and in my new system. I admit the sterilizing steam at a single point. And through its use I sterilize the entire system rapidly and effectively in a quick, thorough, once-through passage of the steam, eflectively sterilizing the valve seat during the course thereof.

With the foregoing in mind, it will be seen that I provide a preferably stainless steel valve-controlled passage 9 having a flange 9a by which it can be clamped to a flange 10 on the gullet outlet 11 leading from the higher pressure chamber 2 and is formed integrally with an elbow 12 adapted for connection to the lower end of the uptake passage 14 which leads in turn to the lower pressure chamber 3. Within the said valve-controlled passage 9 is suitably housed a preferably stainless steel machined butterfly valve 15 which is peripherally grooved to receive an O rin 15a which, when the valve is closed, is adapted to fit neatly within the passage 9 and effect a seal.

The butterfly valve 15 is mounted to a transverse member 16 (Figure 3) having knife edge pivots 16a beyond opposite edges of the butterfly valve, the axis of the pivots 16a passing through the middle of the O ring and the pivots being adapted to pivot in the lower angles of aligned rectangular grooves 9b formed across the end free of the flange 9a of the passage 9. The pivots 16a are prevented from moving out of the grooves 9b by the face of the flange 10 when the apparatus is assembled as shown in Figure 4. Sealing means comprising a ring 17 of any suitable compressible sealing material are located between the flanges 9a and 10 slightly beyond the outer end of the knife edges Me as shown in Figure 2, and serve to isolate the interior of the apparatus from the atmosphere. The said ring is disposed on a shoulder 17a formed on the flange 9a.

At the side of the butterfly valve opposite the transverse member 16 is a tongue 18 fixed to the butterfly valve and extends within the passage 9 upwardly and at an angle as shown in Figure 2. The tongue is engaged on its upper side by the lower end of a dependent stem 19 which is vertically actuable by the rotation of an internally threaded hand nut 20 which screws onto an externally threaded boss 21 projecting upwards from the passage 9, the stem 19 passing through the said boss and being associated with the said hand-nut as shown in Figures 2 and 3 of the accompanying drawings.

On the stem 19 is formed an enlargement 19a which is annularly grooved to receive a sealing O ring 19b which is adapted to effect a permanent seal between the stem 19 and the boss 21 allowing upward and downward controlling or adjusting movements of the stem 19 under influence of the hand-nut 20. It will be obvious that the angle of the butterfly valve can be adjusted or changed by rotation of the hand-nut 20.

On the side of the butterfly valve opposite to the tongue 18 there projects from the said butterfly valve towards the higher pressure chamber 2 an upwardly inclined float arm 22 carrying an elongated float 23 located in the gullet outlet 11. The elongated shape of the float enables it to be readily inserted into and accommodated in position within a small gullet, the arrangement being such that a minimum amount of liquid is required to operate the valve.

Owing to the construction of the butterfly valve with the O ring 15a in its periphery, the said valve does not need to be liquid sealed, a seal being effected by the valve even when it is substantially dry.

Two important characteristics of the valve are that it has substantially balanced areas, and that the knife edge mounting of the butterfly valve is substantially free from friction, with the result that irrespective of the difference between the pressures acting on opposite sides of the valve, and variations in such pressures very little energy is required to operate it and both the weight and buoyancy of the float can therefore be kept to a minimum.

A feature of the construction herein disclosed is that, being readily demountable and being suitable for manufacture in stainless steel, the construction is really hygienic.

In use, after the component parts have been cleaned, and after the assembling of the complete installation of the apparatus of the type described, it is desirable that before commencing to run on liquid, the entire system should be subjected to treatment by live steam under suitable pressure. The steam performs the triple function of expelling the air from the system, heating the installation to a suitable operating temperature and sterilising its interior surfaces.

By manually opening the valve by operation of the handnut 20 hereinbefore described, the live steam treatment of the installation can be effected via the one entry point. Steam introduced at the inlet 8 passes through the pasteuriser 1 and liquid supply pipe 4, and flows through every part of the system including the condenser 6 and discharge pump (not shown) connected at 5, and effectively accomplishes the triple function above referred to.

In normal use, the functioning of the apparatus is clear from the preceding description. The valve not being held open under the influence of the handnut 20, it automatically permits the passage of liquid while the float action prevents the passage of gas or vapour. Though requiring only a small volume of liquid flow for its operation, the valve automatically maintains a liquid seal at all times when it is not held open. The level of the liquid seal being always above the valve, though varying to suit the varying port area required by the valve to meet changes in pressure or rates of flow. Due to the factors previously mentioned the valve is not susceptible to any exterior fluctuations of pressure or the like.

After a run has been completed, to remove from the apparatus the liquid remaining as a seal therein, the valve is manually opened by operation of the handnut 20, and is held in such position by the friction inherent in the design of its associated control or adjusting means above described. Steam introduced at the inlet 8 flows through the apparatus and expels the liquid through the opened valve, the steam carrying the now entrained liquid into the lower pressure chamber where it is separated and removed in the usual manner. It will be clear that in many cases the difference in pressure existing between the two chambers will be sufficient when the valve is further opened to give the requisite velocity to the steam to remove the seal.

A second extremely important feature of my invention may be more thoroughly understood from what has just been said. This has to do with the re-capture of residual liquor remaining at the end of a run. And in this connection it will be recalled that with apparatus of this general type, employing a valve between the chambers 2 and 3, a substantial quantity of liquid will still be entrapped in the region of the passageway 9 and gullet outlet 11, near the valve 15. In a typical ease up to about four or five gallons of liquid will thus be entrapped.

This represents a substantial value. In dairy practices in some countries, where the dairyman is largely concerned with say, butter preparation, re-capture of this liquor presents no diflicult problem. The dairyman simply washes this residual liquor through with a substantial quantity of water. And while it is true that this water comprises a diluent, resulting dilution is relatively unimportant because the fluid is re-concentrated in subsequent stages of treatment.

In this country, however, with its large emphasis upon the production of homogenized milk, ice-cream mixes, market or table cream or the like, water cannot be employed successfully for re-capturing residual liquids. This is because the presence of diluents cannot be tolerated in our practices. Heretofore it has been irrevocably lost. It could not be re-captured from the substantial quantity of water required to wash it from the apparatus. The presence of the water, comprising a diluent, creates an irreversible situation. And this cannot be corrected under our dairy practice in this country.

Accordingly, it is apparent that an important problem confronting our dairy industry has been the recovery of this four to five gallons of this residual liquid which has heretofore comprised wastage. Since this residual liquor comprises a valuable product, obviously it should be recovered if this can be done in manner which is at all convenient.

Accordingly and to achieve this end, at the end of the run, I open the butterfly valve 15 to its fullest extent in the passageway 9. Next, I introduce steam through the single inlet 8, at the beginning of the system. Steam thus admitted passes first through the pasteurizer 1, and then traverses the up-take pipe and chamber 2. It pushes ahead all residual liquid collected at the bottom of chamber 2. Now, and with valve 15 manually adjusted to its fully open position, the steam sweeps this residual liquid through the unrestricted opening of this valve. But when the liquid passes through valve 15 and reaches the passageway 9, it is on the threshold of a higher degree of vacuum, i. e. a region of reduced pressure. And this reduced pressure tends to pull the liquid and steam mixture through the up-take pipe to the lower pressure chamber 3. It acts in conjunction with the steam, and in addition thereto. From chamber 3 the liquor passes to the point of discharge.

When it is desired to dismantle the valve assembly for cleaning purposes, the joints 24 and 25 may first be broken, and the combined passage 9 and elbow 12 removed, together with the valve and float assembly which can now be readily disengaged from the passage 9. After cleansing, the parts can be reassembled in a manner which will be clear from the foregoing description.

In the alternative and less preferred construction shown in Figure of the accompanying drawings, instead of a hand-nut being employed as shown in Figures 1 to 3, there is provided a hook member acting on the side of the butterfly valve toward the chamber 2.

A boss or bearing 26 on the flange 9c is parallel with and above the substantially horizontal part of the passage 9d and a shaft 27 is adapted to slide through the said boss or bearing 26, a seal being efiected between the said shaft and the boss or bearing by means of a small 0 ring 28 fitting within a groove in the shaft.

A nut 29 pivots on the shaft 27 and has an outwardly or upwardly projecting operating lever 30 thereon. The outer end of the shaft 27 is adapted to coact with a loose staple 31 restrained in a groove in the shaft and associated also with the passage 9d in order to prevent or minimise pivotal movement of the shaft 27 upon pivotal operation of the lever 30.

The inner end of the shaft 27 is bent back sharply at an angle as shown at 32 in order to form a hook member, and its terminal end is adapted to bear on the side of the butterfly valve adjacent to the float in order that appropriate pivotal movement of the lever 30 operating through the nut 29 to cause an endwise movement of the shaft 27, will cause a pressure on the face of the butterfly valve adjacent to the float, above the valve pivots, in order to cause pivotal opening movement of the valve. Movement of the lever 30 in the opposite direction will permit closing of the valve under influence of the weight of the float and float arm.

While it is obvious that for most purposes to which the present invention is applicable it is most desirable that in actual operative position, with the liquid passing between the respective chambers, the valve should be of such a nature as to provide substantial equilibrium of pressure on each side, it is to be understood that the use of an unbalanced valve operable in the manner broadly disclosed herein is within the ambit of the present invention.

In an alternative form of the invention, where the butterfly valve is made with a sufliciently high degree of precision, or where a complete seal by the butterfly valve when not operating on liquid is not necessary, the O- ring or equivalent is dispensed with and the necessary degree of sealing is effected between the periphery of the butterfly valve disc and the seat around the same.

Upon recapitulation, it will readily be seen that among other objectives, I accomplish two important results through the practice of my invention. Both are highly advantageous, and each assumes a high degree of practical importance. Each has heretofore been sought separately but without success. They are now achieved through the practice of my invention. This is brought about through my new method and through my new combination of new apparatus. And in turn this new apparatus is achieved through my use of a new type of valve between the second and third stages.

The new results are:

(l) I now make possible thorough and rapid sterilization of the entire system by a once-through passage of steam through the entire system from a single inlet which is located near the inlet end of the assembly.

(2) I achieve full, complete and rapid recovery of all residual liquor after the completion of any run. Following the practice in this country these liquors, in substantial amount, have heretofore comprised wastage.

Moreover, a further advantage results. This further advantage has to do with the mechanical or hydraulic cleaning of the system before sterilization and during the clean-out process. This can be considered as providing a system which while cleaned chemically, has not yet been sterilized. This hydraulic cleaning is accomplished by passing water, perhaps along with cleaning chemicals, through the system until the system is mechanically cleaned, and until all soil has been removed. This mechanical cleaning follows removal of residual liquors by passage of steam. Cleansing water, together retarding barrier to the cleaning water. Particularly in that part of the system which lies beyond the valve when viewed in the direction of liquid flow, such partiallycracked valve appreciably reduces the hydraulic scouring action. Passage of water must endure for a substantial period of time to ensure effective cleaning.

Quite on the contrary, and with my new system just hereinbefore disclosed and employing my new valve, hydraulic scouring action is not materially impeded during cleaning. With the valve fully opened, and with scouring liquid introduced at the inlet end of the system, this fluid courses rapidly through the system. It cleans effectively, and the system is chemically cleaned in a comparatively short period of time.

Moreover, with known constructions, and somewhat surprisingly, hydraulic scouring is not too effective immediately upstream of the valve. This result comes about due to the tendency of the liquid to pond at that point. While such venturi effect as takes place immediately on the downstream side of the valve contributes towards elfective cleaning in that particular region, nevertheless, the overlying effect is one of retarded hydraulic scouring. The net result is that in systems heretofore known appreciable time is required to achieve effective cleaning.

Additionally and with cleaning as heretofore practiced, when the hydraulic scouring or cleaning through the use of chemicals is terminated, a pond of water is left at the bottom of the intermediate stage. This means that to dump this pond of water the machine must be dismantled. According to my new practice, however, this pond does not exist. Therefore it presents no problem. After cleansing it with water, the system is sterilized by the once-through passage of steam therethrough, introduced at the inlet end of the system.

A further advantage of my new construction is that the operator can bring about effective sterilization of the system through opening but a single steam valve.

This is in sharp contrast with the necessity of opening two or more such valves as is true with known constructions. For in my assembly, the valve which is to be opened is the main steam inlet valve itself. And this main valve must be opened in any case, before the automatic safety control system will permit the operation of the system.

In this connection it is to be noted that the more foolproof the system is from a safety standpoint, the better is the system itself. And if safety can be insured in the course of complete sterilization, material advantages result. For if the operator were to fail to open the second steam valve as is required in prior construction, it is entirely possible that through error, he might start the system into operation without first sterilizing the high vacuum side. But if now, he has to rely on the main steam valve as the single source of steam with which to sterilize the system, it is apparent at once that sterilizing steam will be first introduced into the system and pass therethrough. And undoubtedly this would serve as a reminder to the operator that the system required preliminary sterilization.

All the foregoing, as well as many other highly practical advantages, attend the practice of my invention, which may be envisioned from the two-fold standpoint of my new apparatus and my new method of operating the same.

It is apparent that once the broad aspects of my invention are disclosed, many embodiments thereof will readily suggest themselves to those skilled in the art, and as well, many modifications of the present embodiment. Accordingly, I intend the foregoing disclosure to be considered solely by way of illustration, and not as comprising limitations.

I claim:

1. The method, usable at will, of dislodging residual liquid product from an assembled liquid-treating appa= ratus, cleaning said apparatus and thereupon sterilizing the same, and which apparatus includes, as component parts thereof, an inlet at one end of the apparatus and an outlet at the other end thereof, and wherein are provided at least two vacuum stages connected in tandem, normally operating at different degrees of vacuum, the higher of which degrees of vacuum is impressed on the down-stream stage, with a liquid seal valve provided therebetween for automatic operation, at all times during operation, under control of the head of liquid immediately upstream of the valve; which said method comprises the steps of conditioning the liquid seal for subsequent treatment, disposal and discharge of the liquid content thereof by opening the said valve which controls the seal to an extent greater than during the aforesaid automatic operation thereof and to an extent sufficient to provide for substantially unobstructed flow of fluids through the valve; permeating, steam under positive pressure through the entire apparatus, in a once-through, opencircuit passage of the steam; and discharging the steam and any condensate therewith at the outlet end of the apparatus.

2. A liquid-treating apparatus comprising a plurality of series-interconnected chambers, means for imposing different degrees of vacuum on each said chamber, a valve disposed between adjacent chambers and normally responding automatically to variations of liquid level in the upstream chamber, for passing the liquid continuously from the upstream chamber to the downstream chamber while maintaining a liquid seal between the two chambers, means for operating said valve manually and at will, to an extent beyond that occurring during automatic operation and sufiicient both to provide a substantially unobstructed passage for fluid through the valve and to permit the difference in vacuum which maintains in the two chambers between which the valve is interposed to participate, at such times as the valve is manually set, in dislodging the liquid seal towards the chamber of higher vacuum, and means for introducing steam into the apparatus near the inlet end thereof, and upstream of said valve, in a once-through, open-circuit passage, for cleaning the apparatus.

3. In a liquid-treating apparatus comprising a plurality of series-interconnected treating chambers together with means for imposing different degrees of vacuum on each said chamber, means for permitting the passage of liquid from one chamber to the other while constantly maintaining a liquid seal between the chambers during normal operation of the apparatus, thereby effectively preventing during normal operation the passage of vapors and gases, the said means comprising a float-actuated valve automatically responding to the liquid level in the treating chamber immediately upstream of the valve, the extent of such opening under such automatic operatic-n being restrained to an extent sufiicient to ensure retention of said liquid seal, said valve being balanced so that it is substantially unaffected by either difference in pressure in the two chambers which it interconnects or by the rate of flow of liquid therethrough, and means operably connected with such valve to permit manual opening thereof when desired to a greater extent than during automatic operation of the valve, up to and including fully open position, and which is sufiicient to permit blow-by of the liquid forming the seal, together with the substantially uninterrupted passage of steam through the apparatus.

4. In a liquid-treating apparatus, which comprises a plurality of treating chambers which are connected together in series by passage-means defining a generally horizontally-extending passage at the bottoms of adjacent chambers, together with vacuum means for imposing different degrees of vacuum on each said chamber, and as a new manufacture; a valve assembly provided in said passage-means for permitting the passage of liquid from one said treating chamber to the other while constantly maintaining a liquid seal between the chambers during normal operation of the plant, and thereby effectively preventing, during normal operation, the passage of vapors and gases from one treating chamber to the other; the said valve assembly comprising a valve element which is disposed in said passage-means and cooperating with the latter, to control the degree of opening through said passage means, the said valve, in its fully closed position, being disposed normal to said generally horizontal passagemeans; and the said valve element having at one side thereof, a float arm cocked upwardly from the bottom of the treating chamber which is disposed immediately upstream of the valve means; and an elongated float made fast to said float arm and resting on the surface of the liquid within the said upstream chamber, and controlling said valve element through said float arm, the elongated shape of the float being so contoured as to permit its ready insertion in and removal from the passageway immediately upstream of the valve element; the action of said float on said valve element being such as to cause said valve element to respond automatically to variations in the level in the liquid in the treating chamber which is immediately upstream of the valve element, the extent of the opening of the valve element under such automatic operation being so controlled by the valve float that retention of me liquid seal is ensured during normal operation; and means operably connected with such valve element to permit manual opening to an extent which is suflicient to permit both blow-by of the liquid forming the seal together with the substantially uninterrupted passage of steam through the apparatus, said last-mentioned means being capable of opening said valve to its fully open position wherein it lies substantially parallel to the major axis of said passage means.

5. In combination, a liquid-treating apparatus operating under vacuum and having an inlet end and an outlet end, and comprising a two-stage assembly, the stages of which are tandem-connected, with valve means disposed between the stages; and including as part thereof means normally responsive, during operation, in automatic manner, to liquid level in the upstream stage, immediately ahead of the valve means, to provide continuous liquid seal at the valve means while permitting liquid to flow therethrough; means for impressing a desired vacuum in each stage, preselected for each such stage; means operable at the will of the operator to set open the valve means to an extent further than during normal automatic operation, and sufficient to provide a substantially uninterrupted passage through the valve means; and means for admitting steam at the head or inlet end of said apparatus, for once-through, open-circuit passage substantially completely through the apparatus.

6. The method, usable at will, of dislodging residual liquid product from an assembled liquid-treating apparatus, cleaning said apparatus and sterilizing the same, and which apparatus includes, as component parts thereof, a number of connected treating stages, each said stage being susceptible to the imposition thereon, during operation, of a selected degree of absolute pressure and in the presence of which absolute pressure it operates, and which apparatus also includes liquid-controlled valve means for providing automatic valving of liquid from one stage to another while maintaining a liquid seal there'oetween without disturbance of the pressure conditions which prevail in the respective stages during operation; which said method comprises setting open said valve means to an extent appreciably greater than during ordinary operation and which is suflicient to permit ready flow of fluids through said valve means; sweeping out the liquid seal by passing steam under positive pressure through said apparatus from the region of higher pressure therein in the direction of and through the region of lower pressure, and freely through said valve means; intimately cleaning the apparatus with said liquid seal removed, and passing steam 12 through all the component stages of said apparatus and through said valve means.

7. The method, usable at will, of dislodging residual liquid product from an assembled liquid-treating apparatus, cleaning said apparatus and sterilising the same, and which apparatus includes, as component parts thereof, a number of connected treating stages, each said stage being susceptible to the imposition therein, during operation, of a selected degree of absolute pressure and in the presence of which absolute pressure it operates, and which apparatus also includes a head or inlet end, and wherein the treating stages comprise at least two stages connected in tandem, normally operating at dilferent degrees of absolute pressure, the lower of which degrees of absolute pressure is impressed on the down-stream treating stage, with a liquid-sealed valve provided therebetween for automatic operation, at all times during operation, under control of the head of liquid immediately upstream of the valve; which said method comprises the steps of conditioning the liquid seal for subsequent treatment, disposal and discharge of the liquid thereof by opening the said valve which controls the seal to an extent greater than during the aforesaid automatic operation thereof and to an extent sutficient to provide for substantially unobstructed flow of fluids through the valve, and introducing steam under positive pressure through the entire apparatus, from a single region of steam intake near the head or inlet end of the apparatus.

8. The method, usable at will, of sterilizing an assembled liquid-treating apparatus prior to its operation, and following its operation the dislodging of retained liquid and the cleaning of the apparatus; and which apparatus includes, as component parts thereof, a number of connected treating stages, each such stage being susceptible to the imposition therein, during operation, of a separately selected degree of absolute pressure and in the presence of which it operates, and which apparatus also includes liquid-controlled valve means for providing automatic valving of liquid between any two adjacent stages while maintaining a liquid seal therebetween without disturbance of the pressure conditions which prevail therein during operation: which said method comprises opening said valve means through operator control to an extent greater than during the aforesaid automatic valving and suflicient to enable the passage of a flow of steam therethrough sufficient to sterilize the apparatus; dispersing live steam throughout the apparatus and through said opened valve and thereby sterilizing the apparatus; subjecting the apparatus to normal operation; at a selected time following completion of the normal operation of said apparatus, dislodging the liquid which is retained in the seal provided by said valve means following operation of the apparatus, accomplishing this by opening said valve means to an extent suflicient to enable the passage of a flow of steam through said valve and passing steam through said valve, thus opened, into the adjacent downstream stage; and afterwards cleaning the apparatus, prior to subsequent sterilization, with intimate and direct contact with and washing of all parts of the apparatus by the cleaning medium employed.

9. In combination, a valve assembly, which is both automatically operable to limited extent and manually operable from fully closed to fully open position, and a passageway to be controlled by said valve assembly and comprising a housing therefor; said valve assembly including a butterfly valve nicely pivoted in antifriction and balanced manner within said passageway and which is capable of controlling the opening provided thereby, from fully closed to fully opened position; float means provided on said valve for sensitively and automatically setting the valve to predetermined limited extent, dependmg upon and in response to the liquid level maintaining on the upstream side of the passageway; and manuallycontrolled means, also operably associated with said valve, for sensitively setting said valve assembly in manual operation, to desired extent up to fully opened position, said manually-controlled means comprising a peripheral and elongated boss externally carried on said passageway, one end of which boss terminates in and comprises a camming surface; an elongated control shaft extending through said boss and having a re-entrant or hook portion extending into the interior of the passageway on the upstream side of said valve, said hook portion being bodily movable into and out of contact with said butterfly valve, thereby to rock the same on its pivots; and a hand-operable lever having a sleeve portion loosely mounted on the free end of said shaft for relative rotation thereon, and having a camming surface co-acting with that on said boss, whereby rocking of said lever through a vertical angle will provide bodily displacement of said re-entrant portion of said control shaft, against said butterfly valve.

References Cited in the file of this patent UNITED STATES PATENTS 425,108 Richardson Apr. 8, 1890 2,270,540 Mallory Jan. 20, 1942 2,314,455 Murray Mar. 23, 1943 2,657,896 Muller Nov. 3, 1953 2,665,628 Boileau et a1. Jan. 17, 1954 FOREIGN PATENTS 228,342 Switzerland Nov. 16, 1943 

1. THE METHOD, USABLE AT WILL, OF DISLODGING RESIDUAL LIQUID PRODUCT FROM AN ASSEMBLED LIQUID-TREATING APPARATUS, CLEANING SAID APPARATUS AND THEREUPON STERILIZING THE SAME, AND WHICH APPARATUS INCLUDES, AS COMPONENT PARTS THEREOF, AN INLET AT ONE END OF THE APPARATUS AND AN OUTLET AT THE OTHER END THEREOF, AND WHEREIN ARE PROVIDED AT LEAST TWO VACUUM STAGES CONNECTED IN TANDEM, NORMALLY OPERATING AT DIFFERENT DEGREES OF VACUUM, THE HIGHER OF WHICH DEGREES OF VACUUM IS IMPRESSED ON THE DOWN-STREAM STAGE, WITH A LIQUID SEAL VALVE PROVIDED THEREBETWEEN FOR AUTOMATIC OPERATION, AT ALL TIMES DURING OPERATION, UNDER CONTROL OF THE HEAT OF LIQUID IMMEDIATELY UPSTREAM OF THE VALVE; WHICH SAID METHOD COMPRISES THE STEPS OF CONDITIONING THE LIQUID SEAL FOR SUBSEQUENT TREATMENT, DISPOSAL AND DISCHARGE OF THE LIQUID CONTENT THEREOF BY OPENING THE SAID VALUE WHICH CONTROLS THE SEAL TO AN EXTEND GREATER THAN DURING THE AFORESAID AUTOMATIC OPERATION THEREOF AND TO AN EXTEND SUFFICIENT TO PROVIDE FOR SUBSTANTIALLY UNOBSTRUCTED FLOW OF FLUIDS THROUGH THE VALVE; PERMEATING STEAM UNDER POSITIVE PRESSURE THROUGH THE ENTIRE APPARATUS, IN A ONCE-THROUGH, OPENCIRCUIT PASSAGE OF THE STEAM; AND DISCHARGING THE STEAM AND ANY CONDENSATE THEREWITH AT THE OUTLET END OF THE APPARATUS. 